Process of double exposure



Dec. 14 1926. 1,610,410

F. F. BAKER PROCESS OF DOUBLE EXPOSURE Filed Dec: 2. 1925 Patented Dec. 14, 1926.

UNITED STATES FRIENDF. BAKER, GF LANKERSHIIVI, CALEORNIA.

PRCESS F DOUBLE EXPQSURE.

Appncanoni r4filed December This invention has to do with a process of double exposure and it is an' object of the invention to provide a simple, effective and practical process for obtaining two regis- 5 tered images on a single film.

An object of this invention is to provide a process of double exposure by which double exposed motion picture film can be effectively and economically made.`

Another object of 'this invention is to Iprovide a process of double exposure whereby accurate registration of the two exposure on a single film is obtainable.

The objects and features of this invention will be best and more fully understood'from the following detailed description of typical manneisin which it may, be carried out, vthroughout which description reference is had to the accompanying drawings, in

which: j Figs. l, 2 and 3 illustrate diagrammatical- 'ly various steps in carrying out my process,

Fig. l being a view .illustrating the manner.

in which the first exposure -ismade, Fig. 2 being a view illustrating the manner in which the second exposure is made, and Fig.v

3 being a view illustrating the nal or coni-IA pleted film. j I y j Figs. e, 5, 6, 7 and 8 illustrate diagrammatically various steps in another manner of carrying out my invention, Fig. 4 illustrating Vthe manner in which the first ex posure is made, Figs. 5 and 6 illustrating steps whereby secondary films are ina-de, and Figs. and 8 illustrating steps whereby the final film is made from the secondary films.

This invention is particularly valuable commercially as applied to the production oi motion picturefilm, so therefore l will` proceed to describe manners of carrying out the invention particularly suitedfor the production of such film.

lin carrying out the form of the invention illustrated by Figs. l, 2 and 3 of the drawings, the first exposure is made onto two films A and B simultaneously so that the relation of the exposures on the two films 2, 1925. Serial No. 72,720..

theshaft of light from the subject l2 so that it directs light from the subject onto the film B, and openings which allow the light to pass directly onto the filmA. In the case of motion picture apparatus this rotating reflector isoperated in proper synchronism with the movement'mechanism of the camera. The film A is arranged with its emul sion side away from the subject while the film B is arranged with its emulsion side forward or facing the subject. ln 'making this first-exposure the subject l2 is preferably .taken against adark or black baclrground in order that decided contrast be obtainable in the images on the films.

After the lii'st exposure the film B, which l will tei-m the 'matlilnn is developed or treated so that the exposed parts become dark or substantially opaque. The film B thus becomes a mat. The exposed parts of the mat film B may be made opaque by suitable treatment er development, or by dyeing, hand painting, or any other means.

vThe second exposure is made through the mat film B- onto a film C which is to enter into the final negative film. By making the exposure onto the film C through the mat film B the opaque parts on the mat film corresponding to the parts exposed upon the first exposure operate to mat out on the film 'C so that said parts are not exposed to light fr'ornithe subject of the secondexposure. During the second explosurefthe mat film B is arranged with its emulsion side against the film C `so that the matted out parts on the nlm C are correspondingly related vto the exposed parts on film A. The film C is arranged so that its emulsion side faces the nlm B, so that the films have their emulsion sidestogether.

The hlm t exposed during the first exposure, and the film (l exposed during the second exposure through the mat lilm B,

are then cemented or otherwise secured together in registering relation and are developed. Films A and C are cemented together with their emulsion sides out so that the final negative lm, formed or composed of the joined hlm A. and @,'carries the image of the first exposure on one side and the image of the second exposure on the other side, the images being in register.

Positive prints can be made from the final negative, thus produced in an optical printer or other suitable" apparatus. It is to be particularly noted that the films A and C which enterA into the final negative areboth subjected to the same treatment, that is as to the same development, and that the development is preferably made after the films are cemented together thus eliminating inaccuracies inregister of the images on the B are exposed simultaneously upon the first exposure to light from the subject l2, the

light being divided by light dividing means l0v so that the exposures on the films A and Bare in reversed relation.v In this form of my process the films A and B are both developed afterthe first exposure and prints A an-d B are mad-e from them, the print A being made in the usual manner as a positive print, the print B being made on reversal stock, so that it is a negative 4the same as B. The second exposure is made onto a film C through the print film B, made from the film B exposed on the first exposure. During the second exposure the film B is a mat, the developed parts, that is the parts corresponding to those exposed upon the first exposure, operating to mat out those portions of the film C corresponding nto the subject of the first exposure.

After the film C, Which is to be the .finaly negative film, has been exposed upon the second exposure through the mat film B', the image of the first exposure is print-ed onto it from the film' A', the film A being the positive print made from the original film A therefor making a negative image of t-he subject l2 of the first exposure on the film C in register with the parts matted out by the mat film B during the second exposure.

The filmA C having been exposed directly during the second exposure through the mat film B and having` had the image of the first exposure printed onto it as a negative print from the positive print film A, is then developed producing the finished negative. With this manner of carrying out my process the images of the tivo exposures are obtainable in a single emulsion on the final film C and the several films used in the process are subject to corresponding amounts of treatment or development so that their shrinkage is the same.

Having described only a typical preferred form of my invention il do not'ivish to limit myself to the specific details set forth, but Wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall Within the scope of the following claims:

`Having described my invention, l claim: l. A process of double exposure Which includes making the first exposure of the object in a nonaetinic field on tivo films, treating one of the films to render the exposed parts thereof opaque, making the second exposure on a third film through said treated film, and then uniting the other of said rst two films and the third film With the images in registration to form a final composite film. 2. A process of double exposure which includes, making'tlie first exposure of the ob- 'ject in a nonactinic field on tivo films, treating one to render the exposed parts thereofA opaque, making the second exposure on a third film through the treated film, and then permanently uniting the other of said tivo films and said third film with the images superimposed.

A process of double exposure which includes, making the first exposure of the object in a nonactinic field on tivo films, treating one to render the exposed parts thereof opaque, making the second exposure on a third film through the treated film, permanently uniting said third film and the other of said two films with the images su perimposed, and then developing the united films'.

4f. A process of double exposure which includes, making the firstexposure of the object in a nonactinie--feld on tivo films, treating one to render the exposed parts thereof opaque, making the second exposure on a third fiim through the treated film, and then permanently uniting the other of said two films and said third film With the images superimposed and With their emulsion sides out.

5. A process of double exposure which includes, making the first exposure vof the object in a nonactinic field onto tivo' films directly onto the emulsion of one and through the body of thc other, treating the first mentioned film to render its exposed parts opaque, making` the second exposure through the treated film directly onto the emulsion of .a third film, and then permanently uniting the said other film and said third film.

6. A process of double exposure which includes, making' the first exposure of the object in a iionactinic field on tivo films, treating one to render the exposed parts thereof opaque, making the second exposure on a third film through the treats-d film, and then cenienting together the other of said two films and said third film.

7. A vprocess of double exposure which includes, making` the first exposure of the object in a nonactinic field simultaneously on two films directly onto the emulsion of one and through the body of the other, treating sie i ai

the rst mentioned hn' to render its exposed sion sides out, and then developing the ceparts opaque, shrinking said other film 'to' mented films. e

correspond to said treated film, making theV In Witness that I claim the foregoing I. 10 l second exposure onto a third film through*A have hereunto subscribed my name this 18th 5 the treated hn With the emulsion sides of day of November, 1925.

the films together, cementing the third lm and said other film together with their Vemul- FRIEND F. BAKER. 

